Contact maker and breaker



April 28, 1931- A. N. VAN NOSTRAND 1,302,437

CONTACT MAKER AND BREAKER Filed Sept. 29, 1928 i Mi I 1 INVEN OR 8.1 45 7 A TTORNE Y 5 Patented Apr. 28, 1931 UNITE STATES PATENT OFFICE ARLEIGH N. VAN NGSTRIKND, OF FLUSHING, NEW YORK, ASSIGNOR TO TELAU'IO- GRAPH CGRPORA'EEGN, OF NEW YORK, I i. Y., A CORPORATION OF. VIRGINIA CONTACT MAKER AND BREAKER A ilication filed. Seitenieer .r' 1

gg an alternating current source and then ch ige this alternating current into direct cu r it through suitable ap aaratus, as, for enan ole, by a rectifying device of the socalled vacuum tube type. In such telautograph systems it 1 is desirable to have the rectifying apparatus in operation only when the telautograph apparatus is in actual use and, for the sake of convenience, as well as to avoid failures to shut off the current by oversight, it is very important to provide means whereby the operator in starting to operate the transmitter in the usual way will thereby, *ithout any additional manual act, start the rectifying apparatus and when terminating the operation of the transmitter in the usual way will, also without any additional manual act, stop the rectifying apparatus.

The apparatus embodying the present in vention is a circuit maker and breaker particularly advantageous for closing a circuit when the stylus of the telautograph is moved to unison position and for opening such circuit when the stylus is moved away from the unison position, the construction of the said circuit maker and breaker being such that it will act as a spring device to force the stylus away from the unison position and open the said circuit, if for any reason the stylus should be released by the operator when the said stylus is in the unison position. The circuit which is opened and closed in the present example serves as a control circuit for starting and stopping the rectifying apparatus.

By the present invention a circuit maker and breaker is provided which when open will have the contact points si-fiiciently separated so that arcing cannot occur even with relatively high voltages, and yet the relatively widely open contact points may be Serial No. 309,270.

brought in engagement by a relatively small movement of the stylus. Also a high degree of accuracy and durability is attained, so that the positions at which the stylus opens and closes the circuit may be fixed in initially constructing and adjusting the apparatus and will not change materially in any reasonable time. In addition to this there is a relatively strong pressure between the contact points at the initial engagement as will be more fully explained hereinafter, thereby insurin a sure closure of the circuit upon such initial Contact.

While the subject matter of the invention is shown and described in relation to and forming part of a telautograph transmitter it is highly advantageous for use in other situations where similar conditions are to be met.

The drawings illustrate an embodiment of the invention for use with a telautograph transmitter.

In the drawings Fig. 1 is a plan view of the circuit maker and breaker, with some of the parts of a telautograph transmitter adjacent to the circuit maker and breaker.

Fig. 2 is a sectional View of the circuit maker and breaker, and

Fig. 3 a side elevation of the same.

Referring to the drawings, A indicates one curved rheostat of the usual telautograph transmitter ot the variable direct current type, B is the platen, C is the stylus, D is the unison switch, and E one of the operating rods connecting the stylus with one of the bell-crank devices, this bell-crank device serving to move a contact roller over its rheostat. The bell-crank device, above mentioned, cor prises arms 3 and isuitably pivoted to s in a horizontal plane about an axis indicated at 5. The arm 3 carries the usual spring mounted roller 2 which rides over its rheostat A. All of these above mentioned parts are well known elements in telautograph transmitters and hence need not be spe cifically described.

The circuit maker and breaker of the pres ent invention is advantageously located at the right hand side of the rheostats, in which location it is arranged to be operated or actuated upon movement of the right hand bellcrank to its extreme outward position, which occurs when the stylus is brought to the unison position.

In the best embodiment of the invention as shown in the drawings, the circuit making and breaking device is as follows:

A suitable insulating support, in this case consisting of a block 11 of suitable insulating material, is secured to the transmitter frame. To the inner side of this block is secured a pair of contact spring devices and a pair of stop devices for said contact spring devices. The contact spring devices comprise a master contact spring 14 and a secondary contact spring 15, each having acontact point, as indicated at 21 and 22 respectively, these contact points being arranged to engage each other and being each provided with rounded faces. The master contact spring 14 comprises a clamping portion, an intermediate resilient portion and a stiffened outer end portion. The clamping portion of the spring 14 is'provided with two holes for a purpose hereinafter described. The secondary contact spring 15 has a clampingportion provided with two holes, an intermediate resilient portion, and a stiffened hooked end as more fully explained hereinafter. The stop devices comprise master contact spring stop device 19 arranged to limit the movement of the master contact spring 141, and a secondary contact spring stop device 20 to limit the movement of the secondary contact spring 15. Each stop device h'as a clamping portion provided with two holes fora purpose hereinafter explained, and also has a projecting arm to which the terminal of a circuit conductor may be secured, as for example, by soldering. In order to give sufficient rigidityto the stop devices 19 and 20 they may be made of relatively stiff or heavy material which is comparatively unyielding.

Thestop device 19, for the master contact spring 14, is provided with an inturned end having-an edge arranged to be can ;ed by the stiffened portion of the master contact spring, the latter being so formed that it will tend to press relatively strongly against said edge of the stop device 19. The stop device 20 for the secondary spring is so arranged that its free end will project into the hook of the stiffened hooked end of said secondary contact spring 15, and the latter is so formed that it has such a tendency to move toward the master contact spring let that the hooked end will press relatively strongly against its stop device 20. The stop devices 19 and 20 are so formed that when each is engaged by its respective contact spring, the contact points of said springs will be out of contact with each other and the circuit which includes them will be broken so that no arcing can take place across the gap, the amount of separation of the contact points depending, of course, on the voltage of the circuit.

The contact springs and their stop devices are held rigid relation by two screws, 12, 13, passing through the holes in the clamping portions of said springs and stop devices, and by bushed insulating washers. The bushed insulating washers comprise inter mediate washers 16 and outer washers 18. The washers 16 are located between the contact springs, and have their bushings extended through the holes in the secondary contact spring 15 and into those in its stop device. The outer washers 18 are located outside the stop device 19 and have their bushings extend ed through the holes in the stop device 19 and into those in the master contact spring. The portions of the screws 12 and 13 projecting beyond the bushed insulating washers 18 are provided, next to the said washers 18 with metal washers 26; also with spring locking washers 27 next to the metal washers 26, and with nuts 17 outside the locking washers. When the nuts 17 are screwed up i'irn'ily the contact springs and their stop devices are clamped firmly in proper relation to each other and are rigidly secured to the insulated mounting-block 11. Each contact spring is in electrical contact with its stop device as will be clear from the drawings.

Reference has been made heretofore to the stiffened lever portion of the master contact spring 1 1. lVhile this stiffening may be accomplished in various ways, it has been found satisfactory to accomplish this by providing the contact spring with ribs or flanges along edges. In practice it is advantageous to have these ribs or flanges extend from the free end of the contact spring 14.- inward toward the clamped end of the spring far enough to include all or nearly all of the contact point 21 within the ribbed or fianged'portion. The stiffened portion of the master contact spring extends beyond its stop deviw and beyond the secondary contact spring, so as to be in the path of movement of the actuator 7 which is carried by the arm 3 of the bell-crank.

The hooked end of the secondary contact spring may be stiffened in any suitable wa y. One simple way is to form ribs or flanges on the hooked portion, as indicated at 23.

The result of stiffening the free end of the master contact spring 14 is to confine all bending of the spring to the resilient portion which extends between the stiffened portion and the clamping portion, the latter being held rigidly by the and washers. is the stiffened portion of the master contact spring rests against its stop device 19 the actuator 7 will encounter the master contact spring and begin to move the latter always at the same angular position of the bellcrank and the amount of such movement is substantially in direct proportion to the movement of the actuator. Asthe space between the contacts 21 and 22 in the resting, open position of the contacts is determined in part by the stiffened hook end of the secondary contact spring which is in engagement with its stop device 20, this space is always constant because of the substantially unyielding nature of such hook and stop device. Hence the angular movement of the bellcrank and its actuator necessary to bring the two contacts 21 and 22 into engagement and close the circuit is substantially invariable. Thus, it is possible to obtain great accuracy of setting and of operation so that only a rela tively small angular movement of the bellcrank arm 3 is required to close the control circuit for starting the rectifying apparatus while giving a relatively large gap or break between the contact points. In order to maintain the same writing space at the transmitter free of any mechanical resistance due to action of the springs of the contact maker and breaker the unison switch at the transinitter is located slightly further away from the platen, usually about one-fourth inch more than before, this allowing for the addi tional movement of the stylus necessary for the operation of the circuit maker and breaker.

In order to stop the outward movement of the bell-crank arm 3, a fixed stop device is provided; Inthe present example this consists of a stop-plate 25 provided with a flanged outer end to contact with the bellcrank arm 3, the stop-plate 25 being secured to the block 11 by suitable means, such as the screws shown in the drawings. It is to be noted that the stop-plate is so located that it will stop the bell-crank arm 3 shortly after this arm has brought the contact points 21 and 22 into engagement with each other and before the secondary contact spring 23 can touch the stop-device 20. This avoids unnecessary straining of the contact spring 23, yet insures a positive engagement of the two contact points 21 and 22. If the stylus should be released by the operator when the contact points are still in engagement, the contact springs will serve to force the bellcrank arm and the stylus out of the unison position and will open the circuit by separating the contact points. The master contact spring 14 principally accomplishes this movement, but of course is assisted in starting the movement by the resiliency of the secondary contact spring 15 which follows the movement of the master contact spring 14 until stopped by the hooked end engaging the stop device 20 after which the master contact spring 14 moves toward its own stop device 19 until its stiffened portion rests firmly against the edge of the outer end of the stop device 19.

It is an important advantage of the invention, that because the contact springs 14 and 15 are separated considerably, their contact points swing in different arcs, thus giving a wiping or rubbing action of the contacting faces of said contact points after they have made a contact. This wiping action is sutilcient to maintain the contact faces clean.

The actuator 7 mounted on the bell-crank 3 may be a disk of any relatively hard insulating material held to the bell-crank 3 by a screw or rivet as shown.

It is to be noted that by giving the secondary contact spring 15 such a set that it will press strongly against its stop device 20, an equivalent pressure will be necessary, acting against the contact point of such secondary contact spring, to force the latter away from its stop device. Therefore, when the master contact point of the contact switch initially engages the coacting contact point of the secondary contact spring, a relatively heavy contact pressure is developed before the secondary contact spring starts its movement. This insures a low resistance at the contact faces and a certain closure of the circuit at the predetermined position of the bell-crank arm and its actuator, which would notbe true if the secondar contact spring was easily displaced from its normal position.

lVhat I claim is:

1. In a circuit maker and breaker, the combination, with a pair of stop devices, each arranged to be connected to one terminal of an electric circuit, a master contact sprin tending to press against the adjacent one of said stop devices, a secondary contact spring provided with a hooked end into which the free end of the other stop device enters, said secondary contact spring tending to press its hooked end against its stop device, said contact springs being located be tween said stop devices and provided with contact points facing each other and normally out of contact ith each other when the contact springs are stopped by their respective stop devices, each contact spring being in electrical communication with its respective stop device, means for holding said contact springs and their respective stop devices with the springs separated from each other at the holding means, and an actuator arranged to engage the master contact spring and move it into contact with the secondary contact spring and to move the latter toward its stop device, the master contact spring serving to return the actuator and open the circuit through the contact points when the actuator is released.

2. In a circuit maker and breaker, the combination, with a pair of stop devices. each arranged to be connected to one termi nal of an electric circuit, a master contact spring tending to press against the adjacent one of said stop devices, said master contact spring being provided with a stiffened free end, a secondary cont-act spring provided with a hooked end into which the free end of the other stop device enters, said secondary contact spring tending to press its hooked end against its stop device, said contact springs being located between said stop de vices and provided with contact points facing each other and normally out of contact with each other when the contact springs are stopped by their respective stop devices, each contact spring being in electrical communication with its respective stop device, means for holding said contact springs and their respective stop devices with the springs separated from each other at the holding means, and an actuator arranged to engage the stiliened free end of. the master contact spring and move said spring into contact with the secondary contact spring and to move the latter toward its stop device, the master contact spring serving to return the actuator and open the circuit through the contact points when the actuator is released.

3. In a circuit maker and-breaker, the combination, with a pair of stop devices, each arranged to be connected to one terminal of an electric circuit, a master contact spring tending to press against the adjacent one of said stop devices, a secondary contact spring provided with a hooked end into which the free end of the other stop device enters, said secondary contact spring tending to press its hooked end against its stop device, said contact springs being located between said stop devices and provided with contact points facing each other and normally out of contact with each other when the contact springs are stopped by their respective stop devices, each contact spring being in electrical communication with its respective stop device, means for holding said contact springs and their respective stop devices with the springs separated from each other at the holding means, an actuator arranged to engage the master contact spring and move it into contact with the secondary contact spring and .to move the latter toward its stop device, the master contact spring serving to return the actuator and open the circuit through the contact points when the actuator is released, and means for limiting the movement of the actuator in closing the circuit through the contact springs.

4. A master Contact spring and a secondary con-tact spring each having contact points, the master contact spring tending to move away from the secondary contact spring. and the latter tending to move toward the master contact spring, a stop device for limiting the movement of the secondary contact spring toward the master contact spring, against which stop device the secondary contact spring in its normal position presses strongly, a stop device for limiting the movement of the master contact spring away from the secondary contact spring, said stop devices being arranged to stop their springs with their contact points separated sufliciently to open the circuit, an actuator arranged to move the master contact spring toward the secondary contact spring and to carry the latter away from its normal position, and means for limiting the movement of the actuator in its contactclosing direction.

5. A master contact spring and a secondary contact spring each having contact points, the master contact spring tending to move away from the secondary contact spring. and the latter tending to move toward the master contact spring. the master contact spring having a projecting stiffened end. a stop device for limiting the movement of the secondary contact spring toward the master contact spring, against which stop device the secondary contact spring in its normal position presses strongly, a stop device for limiting the movement of the master contact spring away from the secondary contact spring, said stop devices being arranged to stop their springs with their contact points separated sufliciently to open the circuit. an actuator arranged to engage the projecting stiffened end of the master contact spring to move it toward the secondary contact spring and to carry the latter away from its normal position. and means for limiting the movement of the actuator in its contact-closing direction.

In testimony whereof, Ihave hereunto set my hand.

,ARLEIGH N. VAN NOSTRAND. 

